Luminance enhancement film, backlight module and liquid crystal display device

Abstract

The present invention provides a luminance enhancement film which is superior in dimensional stability, thermal stability, and anti-deformation ability. Thus, it can meet the current requirement for thinning LCD apparatuses. With regard to the luminance enhancement film, a prism row structure is formed on a surface of a substrate, and a reinforced layer is formed on the other surface of the substrate. The glass transition temperature of the reinforced layer is in the range from 80° C. to 250° C., and the thickness of that is in the range from 3 μm to 50 μm.

What is claimed is: 
     
       1. A luminance enhancement film, comprising:
 a support substrate having a first surface and a second surface opposite to the first surface; 
 a prismatic structure comprising a plurality of prisms extending in a first direction, wherein the first surface of the support substrate supports the prismatic structure; and 
 a homogeneous reinforced layer having a third surface and a fourth surface opposite to the third surface, wherein the third surface of the homogeneous reinforced layer is disposed on the second surface of the support substrate, wherein the homogeneous reinforced layer increases the rigidity of the luminance enhancement film without using the fourth surface of the homogeneous reinforced layer for connecting with another element, wherein the glass transition temperature (Tg) of the homogeneous reinforced layer is in the range from 80° C. to 250° C. and the thickness of the homogeneous reinforced layer is in the range from 3 μm to 50 μm. 
 
     
     
       2. The luminance enhancement film of  claim 1 , wherein the glass transition temperature (Tg) of the homogeneous reinforced layer is in the range from 100° C. to 200° C. 
     
     
       3. The luminance enhancement film of  claim 1 , wherein the refractive index of the homogeneous reinforced layer is in the range from 1.3 to 1.6. 
     
     
       4. The luminance enhancement film of  claim 2 , wherein the refractive index of the homogeneous reinforced layer is in the range from 1.3 to 1.6. 
     
     
       5. The luminance enhancement film of  claim 1 , wherein the materials of the homogeneous reinforced layer are acrylic copolymers. 
     
     
       6. The luminance enhancement film of  claim 5 , wherein the acrylic copolymers are those copolymerized from aliphatic acrylic mono- or oligomers and aromatic multifunctional acrylic mono- or oligomers, or aromatic acrylic mono- or oligomers and aliphatic multifunctional acrylic mono- or oligomers. 
     
     
       7. The luminance enhancement film of  claim 1 , wherein the homogeneous reinforced layer comprises particles whose particle diameter is in the range from 1 μm to 20 μm. 
     
     
       8. The luminance enhancement film of  claim 7 , wherein the particles are selected from at least one of organic particles and inorganic particles. 
     
     
       9. The luminance enhancement film of  claim 1 , wherein a plurality of projecting bodies are formed on the surface of the homogeneous reinforced layer. 
     
     
       10. The luminance enhancement film of  claim 9 , wherein the shape of the projecting bodies is selected from at least one of triangle cylinder, irregular shape, semi-cylinder, hemispherical shape and semi-elliptical shape and wherein the arrangement between projecting bodies is regular or random. 
     
     
       11. The luminance enhancement film of  claim 1 , wherein the thickness of the support substrate is in the range from 25 μm to 300 μm. 
     
     
       12. The luminance enhancement film of  claim 11 , wherein the support substrate is selected from one of polyethylene terephthalate (PET), polycarbonate (PC), polyethylene naphthalate (PEN), (metallocene) cyclic olefin copolymer (mCOC), polyarylate (PAR), polyethersulfone (PES), triacetate cellulose (TAC) and polymethyl methacrylate (PMMA). 
     
     
       13. The luminance enhancement film of  claim 1 , wherein the glass transition temperature (Tg) of the homogeneous reinforced layer is larger than the glass transition temperature of the support substrate. 
     
     
       14. The luminance enhancement film of  claim 1 , wherein the third surface of the homogeneous reinforced layer is completely in contact with the second surface of the support substrate. 
     
     
       15. A luminance enhancement film, comprising:
 a support substrate having a first surface and a second surface opposite to the first surface; 
 a prismatic structure comprising a plurality of prisms extending in a first direction, wherein the first surface of the support substrate supports the prismatic structure; and 
 a homogeneous reinforced layer having a third surface and a fourth surface opposite to the third surface, wherein the third surface of the homogeneous reinforced layer is disposed on the second surface of the support substrate, wherein the homogeneous reinforced layer increases the rigidity of the luminance enhancement film without using the fourth surface of the homogeneous reinforced layer for connecting with another element. 
 
     
     
       16. The luminance enhancement film of  claim 15 , wherein the glass transition temperature (Tg) of the homogeneous reinforced layer is larger than the glass transition temperature of the support substrate. 
     
     
       17. The luminance enhancement film of  claim 15 , wherein the third surface of the homogeneous reinforced layer is completely in contact with the second surface of the support substrate. 
     
     
       18. A luminance enhancement film, comprising:
 a support substrate having a first surface and a second surface opposite to the first surface; 
 a prismatic structure comprising a plurality of prisms extending in a first direction, wherein the first surface of the support substrate supports the prismatic structure; and 
 a homogeneous reinforced layer having a third surface and a fourth surface opposite to the third surface, wherein the third surface of the homogeneous reinforced layer is disposed on the second surface of the support substrate, wherein the homogeneous reinforced layer increases the rigidity of the luminance enhancement film to avoid the deformation of the luminance enhancement film resulting from heat without using the fourth surface of the homogeneous reinforced layer for connecting with another element. 
 
     
     
       19. The luminance enhancement film of  claim 18 , wherein the glass transition temperature (Tg) of the homogeneous reinforced layer is larger than the glass transition temperature of the support substrate. 
     
     
       20. The luminance enhancement film of  claim 18 , wherein the third surface of the homogeneous reinforced layer is completely in contact with the second surface of the support substrate.